On effects of weights in spatial interpolation

Nowadays, GIS software systems provide some generic interpolation methods. Errors may occure due to inappropriate setting of parameters. For example, in IDW, the default value of exponent is 2. But experiments prove that 2 may not be the best. This article discusses the inverse distance weighted method and the spline Functions. It was found that: (1) The choice of weights of IDW has great impact on interpolation results, we must choose the exponent according to the specific circumstances in the problem domain; (2) In some areas, data points are scarce or missing, increasing the exponential value of IDW appropriately can improve the results; (3) In comparison to IDW, splines are more suitable for situations where surface changes gradually, such as temperature, elevation, groundwater temperature, concentration of pollution, and so on.